diff --git a/packages/@uppy/tus/src/index.ts b/packages/@uppy/tus/src/index.ts
index 4480dd5e48..97adb68164 100644
--- a/packages/@uppy/tus/src/index.ts
+++ b/packages/@uppy/tus/src/index.ts
@@ -220,8 +220,8 @@ export default class Tus<M extends Meta, B extends Body> extends BasePlugin<
 
     // Create a new tus upload
     return new Promise<tus.Upload | string>((resolve, reject) => {
-      let queuedRequest: RateLimitedQueue.QueueEntry
-      let qRequest: () => void
+      let queuedRequest: ReturnType<RateLimitedQueue['run']>
+      let qRequest: () => () => void
       let upload: tus.Upload
 
       const opts = {
diff --git a/packages/@uppy/utils/src/RateLimitedQueue.test.js b/packages/@uppy/utils/src/RateLimitedQueue.test.ts
similarity index 94%
rename from packages/@uppy/utils/src/RateLimitedQueue.test.js
rename to packages/@uppy/utils/src/RateLimitedQueue.test.ts
index da2b000cc4..9acdb74f35 100644
--- a/packages/@uppy/utils/src/RateLimitedQueue.test.js
+++ b/packages/@uppy/utils/src/RateLimitedQueue.test.ts
@@ -1,10 +1,10 @@
 import { describe, expect, it } from 'vitest'
-import { RateLimitedQueue } from './RateLimitedQueue.js'
+import { RateLimitedQueue } from './RateLimitedQueue.ts'
 import delay from './delay.ts'
 
 describe('RateLimitedQueue', () => {
   let pending = 0
-  function fn() {
+  async function fn() {
     pending++
     return delay(15).then(() => pending--)
   }
diff --git a/packages/@uppy/utils/src/RateLimitedQueue.js b/packages/@uppy/utils/src/RateLimitedQueue.ts
similarity index 66%
rename from packages/@uppy/utils/src/RateLimitedQueue.js
rename to packages/@uppy/utils/src/RateLimitedQueue.ts
index 9daecf6b2b..1c769e9a19 100644
--- a/packages/@uppy/utils/src/RateLimitedQueue.js
+++ b/packages/@uppy/utils/src/RateLimitedQueue.ts
@@ -1,34 +1,58 @@
-function createCancelError (cause) {
+function createCancelError(cause?: string) {
   return new Error('Cancelled', { cause })
 }
 
-function abortOn (signal) {
+function abortOn(
+  this: { abort: (cause: string) => void; then?: Promise<any>['then'] },
+  signal?: AbortSignal,
+) {
   if (signal != null) {
     const abortPromise = () => this.abort(signal.reason)
     signal.addEventListener('abort', abortPromise, { once: true })
-    const removeAbortListener = () => { signal.removeEventListener('abort', abortPromise) }
+    const removeAbortListener = () => {
+      signal.removeEventListener('abort', abortPromise)
+    }
     this.then?.(removeAbortListener, removeAbortListener)
   }
 
   return this
 }
 
+type Handler = {
+  shouldBeRequeued?: boolean
+  fn: () => (...args: any[]) => Promise<void> | void
+  priority: number
+  abort: (cause?: unknown) => void
+  done: () => void
+}
+
+type QueueOptions = {
+  priority?: number
+}
+
+interface AbortablePromise<T> extends Promise<T> {
+  abort(cause?: unknown): void
+  abortOn: typeof abortOn
+}
+
 export class RateLimitedQueue {
   #activeRequests = 0
 
-  #queuedHandlers = []
+  #queuedHandlers: Handler[] = []
 
   #paused = false
 
-  #pauseTimer
+  #pauseTimer: ReturnType<typeof setTimeout>
 
   #downLimit = 1
 
-  #upperLimit
+  #upperLimit: number
+
+  #rateLimitingTimer: ReturnType<typeof setTimeout>
 
-  #rateLimitingTimer
+  limit: number
 
-  constructor (limit) {
+  constructor(limit?: number) {
     if (typeof limit !== 'number' || limit === 0) {
       this.limit = Infinity
     } else {
@@ -36,12 +60,12 @@ export class RateLimitedQueue {
     }
   }
 
-  #call (fn) {
+  #call(fn: Handler['fn']) {
     this.#activeRequests += 1
 
     let done = false
 
-    let cancelActive
+    let cancelActive: (cause?: unknown) => void
     try {
       cancelActive = fn()
     } catch (err) {
@@ -50,7 +74,7 @@ export class RateLimitedQueue {
     }
 
     return {
-      abort: (cause) => {
+      abort: (cause?: unknown) => {
         if (done) return
         done = true
         this.#activeRequests -= 1
@@ -67,14 +91,14 @@ export class RateLimitedQueue {
     }
   }
 
-  #queueNext () {
+  #queueNext() {
     // Do it soon but not immediately, this allows clearing out the entire queue synchronously
     // one by one without continuously _advancing_ it (and starting new tasks before immediately
     // aborting them)
     queueMicrotask(() => this.#next())
   }
 
-  #next () {
+  #next() {
     if (this.#paused || this.#activeRequests >= this.limit) {
       return
     }
@@ -86,20 +110,25 @@ export class RateLimitedQueue {
     // so that cancelling it does the Right Thing (and doesn't just try
     // to dequeue an already-running request).
     const next = this.#queuedHandlers.shift()
+    if (next == null) {
+      throw new Error('Invariant violation: next is null')
+    }
     const handler = this.#call(next.fn)
     next.abort = handler.abort
     next.done = handler.done
   }
 
-  #queue (fn, options = {}) {
-    const handler = {
+  #queue(fn: Handler['fn'], options?: QueueOptions) {
+    const handler: Handler = {
       fn,
-      priority: options.priority || 0,
+      priority: options?.priority || 0,
       abort: () => {
         this.#dequeue(handler)
       },
       done: () => {
-        throw new Error('Cannot mark a queued request as done: this indicates a bug')
+        throw new Error(
+          'Cannot mark a queued request as done: this indicates a bug',
+        )
       },
     }
 
@@ -114,22 +143,27 @@ export class RateLimitedQueue {
     return handler
   }
 
-  #dequeue (handler) {
+  #dequeue(handler: Handler) {
     const index = this.#queuedHandlers.indexOf(handler)
     if (index !== -1) {
       this.#queuedHandlers.splice(index, 1)
     }
   }
 
-  run (fn, queueOptions) {
+  run(
+    fn: Handler['fn'],
+    queueOptions?: QueueOptions,
+  ): Handler | Omit<Handler, 'fn' | 'priority'> {
     if (!this.#paused && this.#activeRequests < this.limit) {
       return this.#call(fn)
     }
     return this.#queue(fn, queueOptions)
   }
 
-  wrapSyncFunction (fn, queueOptions) {
-    return (...args) => {
+  wrapSyncFunction(fn: () => void, queueOptions: QueueOptions) {
+    return (
+      ...args: Parameters<Handler['fn']>
+    ): { abortOn: typeof abortOn; abort: Handler['abort'] } => {
       const queuedRequest = this.run(() => {
         fn(...args)
         queueMicrotask(() => queuedRequest.done())
@@ -138,19 +172,22 @@ export class RateLimitedQueue {
 
       return {
         abortOn,
-        abort () {
+        abort() {
           queuedRequest.abort()
         },
       }
     }
   }
 
-  wrapPromiseFunction (fn, queueOptions) {
-    return (...args) => {
-      let queuedRequest
+  wrapPromiseFunction<T extends (...args: any[]) => any>(
+    fn: T,
+    queueOptions?: QueueOptions,
+  ) {
+    return (...args: Parameters<T>): AbortablePromise<ReturnType<T>> => {
+      let queuedRequest: ReturnType<RateLimitedQueue['run']>
       const outerPromise = new Promise((resolve, reject) => {
         queuedRequest = this.run(() => {
-          let cancelError
+          let cancelError: ReturnType<typeof createCancelError>
           let innerPromise
           try {
             innerPromise = Promise.resolve(fn(...args))
@@ -158,27 +195,30 @@ export class RateLimitedQueue {
             innerPromise = Promise.reject(err)
           }
 
-          innerPromise.then((result) => {
-            if (cancelError) {
-              reject(cancelError)
-            } else {
-              queuedRequest.done()
-              resolve(result)
-            }
-          }, (err) => {
-            if (cancelError) {
-              reject(cancelError)
-            } else {
-              queuedRequest.done()
-              reject(err)
-            }
-          })
+          innerPromise.then(
+            (result) => {
+              if (cancelError) {
+                reject(cancelError)
+              } else {
+                queuedRequest.done()
+                resolve(result)
+              }
+            },
+            (err) => {
+              if (cancelError) {
+                reject(cancelError)
+              } else {
+                queuedRequest.done()
+                reject(err)
+              }
+            },
+          )
 
           return (cause) => {
             cancelError = createCancelError(cause)
           }
         }, queueOptions)
-      })
+      }) as AbortablePromise<ReturnType<T>>
 
       outerPromise.abort = (cause) => {
         queuedRequest.abort(cause)
@@ -189,7 +229,7 @@ export class RateLimitedQueue {
     }
   }
 
-  resume () {
+  resume(): void {
     this.#paused = false
     clearTimeout(this.#pauseTimer)
     for (let i = 0; i < this.limit; i++) {
@@ -205,7 +245,7 @@ export class RateLimitedQueue {
    * @param {number | null } [duration] Duration for the pause to happen, in milliseconds.
    *                                    If omitted, the queue won't resume automatically.
    */
-  pause (duration = null) {
+  pause(duration: number | null = null): void {
     this.#paused = true
     clearTimeout(this.#pauseTimer)
     if (duration != null) {
@@ -223,7 +263,7 @@ export class RateLimitedQueue {
    *
    * @param {number} duration in milliseconds.
    */
-  rateLimit (duration) {
+  rateLimit(duration: number): void {
     clearTimeout(this.#rateLimitingTimer)
     this.pause(duration)
     if (this.limit > 1 && Number.isFinite(this.limit)) {
@@ -250,7 +290,9 @@ export class RateLimitedQueue {
     }
   }
 
-  get isPaused () { return this.#paused }
+  get isPaused(): boolean {
+    return this.#paused
+  }
 }
 
 export const internalRateLimitedQueue = Symbol('__queue')